Document and Entity Information Statement [Table] Statement [Line Items] Statement Entity Registrant Name Entity Central Index Key Document Type Document Period End Date Amendment Flag Document Fiscal Period Focus Document Fiscal Year Focus Current Fiscal Year End Date Trading Symbol Entity Current Reporting Status Entity Filer Category Entity Emerging Growth Company Entity Small Business Entity Common Stock, Shares Outstanding Condensed Consolidated Balance Sheets Assets [Abstract] Assets Assets, Current [Abstract] Current assets: Cash and Cash Equivalents, at Carrying Value Cash and cash equivalents Debt Securities, Available-for-sale, Current Marketable securities Prepaid Expense and Other Assets, Current Prepaid expenses and other current assets Assets, Current Total current assets Property, Plant and Equipment, Net Property and equipment, net Operating Lease, Right-of-Use Asset Right-of-use asset Assets Total assets Liabilities and Equity [Abstract] Liabilities and Stockholders' Equity Liabilities, Current [Abstract] Current liabilities: Accounts Payable, Current Accounts payable Accrued Liabilities, Current Accrued expenses Operating Lease, Liability, Current Lease liability, current Liabilities, Current Total current liabilities Liabilities, Noncurrent [Abstract] Long-term liabilities: Operating Lease, Liability, Noncurrent Lease liability, long term Liabilities, Noncurrent Total long-term liabilities Liabilities Total liabilities Stockholders' Equity Attributable to Parent [Abstract] Stockholders' equity: Preferred Stock, Value, Issued Preferred stock, par value $0.0001 per share authorized: 5,000,000 shares at March 31, 2019 and December 31, 2018; 1,969,797 shares issued and outstanding at March 31, 2019 and December 31, 2018 Common Stock, Value, Issued Common stock, par value $0.0001 per share authorized: 200,000,000 at March 31, 2019 and December 31, 2018; 15,417,064 and 15,409,023 shares issued and outstanding at March 31, 2019 and December 31, 2018, respectively Additional Paid in Capital, Common Stock Additional paid-in-capital Accumulated Other Comprehensive Income (Loss), Net of Tax Accumulated other comprehensive gain (loss) Retained Earnings (Accumulated Deficit) Accumulated deficit Accumulated deficit Stockholders' Equity Attributable to Parent Balance Balance Total stockholders' equity Liabilities and Equity Total liabilities and stockholders' equity Preferred Stock, Par or Stated Value Per Share Preferred stock, par value (in dollars per share) Preferred Stock, Shares Authorized Preferred stock, shares authorized Preferred Stock, Shares Issued Preferred stock, shares issued Preferred Stock, Shares Outstanding Preferred stock, shares outstanding Common Stock, Par or Stated Value Per Share Common stock, par value (in dollars per share) Common Stock, Shares Authorized Common stock, shares authorized Common Stock, Shares, Issued Balance (in shares) Balance (in shares) Common stock, shares issued Common Stock, Shares, Outstanding Common stock, shares outstanding Condensed Consolidated Statements of Operations Costs and Expenses [Abstract] Operating expenses: Research and Development Expense (Excluding Acquired in Process Cost) Research and development General and Administrative Expense General and administrative Operating Expenses Total operating expenses Operating Income (Loss) Loss from operations Interest Income, Other Interest income Net Income (Loss) Attributable to Parent Net loss Net loss Net loss Net Loss Earnings Per Share [Abstract] Net loss per common share: Earnings Per Share, Basic and Diluted Basic and diluted net loss per common share (in dollars per share) Weighted Average Number of Shares Outstanding, Basic and Diluted Basic and diluted weighted average number of common shares outstanding Condensed Consolidated Statements of Comprehensive Loss Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent [Abstract] Other comprehensive income (loss): Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax, Portion Attributable to Parent Unrealized gain (loss) on available-for-sale securities Unrealized loss on marketable securities Comprehensive Income (Loss), Net of Tax, Attributable to Parent Comprehensive loss Condensed Consolidated Statements of Stockholders' Equity Equity Components [Axis] Equity Component [Domain] Equity Component [Domain] Common Stock [Member] Common stock Additional Paid In Capital [Member] Additional paid-in Capital Accumulated Other Comprehensive Income [Member] Accumulated other comprehensive income (loss) Retained Earnings [Member] Accumulated deficit Increase (Decrease) in Stockholders' Equity [Roll Forward] Increase (Decrease) in Stockholders' Equity Stock Issued During Period, Value, Stock Options Exercised Exercise of common stock options Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Options exercised (in shares) Exercise of common stock options (in shares) Adjustments to Additional Paid in Capital, Share-based Compensation, Stock Options, Requisite Service Period Recognition Compensation expense related to stock options for services Condensed Consolidated Statements of Cash Flows Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract] Cash flows from operating activities: Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net loss Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Adjustments to reconcile net loss to net cash used in operating activities: Share-based Compensation Stock-based compensation expense Depreciation, Depletion and Amortization Depreciation and amortization expense Increase (Decrease) in Operating Capital [Abstract] Changes in operating assets and liabilities: Increase (Decrease) in Prepaid Expense and Other Assets Prepaid expenses and other current assets Increase (Decrease) in Accounts Payable, Trade Accounts payable Increase (Decrease) in Accrued Liabilities Accrued expense The increase (decrease) during the reporting period in the aggregate amount of accrued interest expense incurred but not yet paid, net of interest received on maturity of investments. Increase (Decrease) In Accrued Interest, Net Of Interest Received Accrued interest, net of interest received on maturity of investments Net Cash Provided by (Used in) Operating Activities, Continuing Operations Net cash used in operating activities Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract] Cash flows from investing activities: Payments to Acquire Marketable Securities Purchases of marketable securities Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities Sales and maturities of marketable securities Payments to Acquire Property, Plant, and Equipment Purchases of property and equipment, net of disposals Net Cash Provided by (Used in) Investing Activities, Continuing Operations Net cash used in investing activities Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract] Cash flows from financing activities: The cash inflow from the additional capital contribution including exercise of common stock options to the entity. Proceeds From Issuance of Common Stock Including Exercise of Common Stock Options Proceeds from exercise of common stock options Net Cash Provided by (Used in) Financing Activities, Continuing Operations Net cash provided by financing activities Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect Net decrease in cash and cash equivalents Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents Cash and cash equivalents at end of period Cash and cash equivalents at beginning of period Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Supplemental disclosure of cash flow information: Right-of-Use Asset Obtained in Exchange for Operating Lease Liability Acquisition of a right-of-use asset in exchange for a lease liability Organization, Business and Basis of Presentation Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Organization, Business and Basis of Presentation Summary of Significant Accounting Policies Organization, Consolidation, Basis of Presentation, Business Description and Accounting Policies [Text Block] Summary of Significant Accounting Policies Liquidity And Uncertainties Disclosure Abstract Liquidity and Uncertainties Substantial Doubt about Going Concern [Text Block] Liquidity and Uncertainties Cash, Cash Equivalents and Marketable Securities Cash, Cash Equivalents, and Marketable Securities [Text Block] Cash, Cash Equivalents and Marketable Securities Stockholders' Equity Stockholders' Equity Note Disclosure [Text Block] Stockholders' Equity Stock-based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-based Compensation Leases Leases of Lessee Disclosure [Text Block] Leases Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Commitments and Contingencies Consolidation, Policy [Policy Text Block] Principle of Consolidation Use of Estimates, Policy [Policy Text Block] Use of Estimates Cash and Cash Equivalents, Policy [Policy Text Block] Cash and Cash Equivalents Marketable Securities, Policy [Policy Text Block] Marketable Securities Fair Value of Financial Instruments, Policy [Policy Text Block] Fair Value of Financial Instruments Research and Development Expense, Policy [Policy Text Block] Research and Development Costs Disclosure of accounting policy for patents. Patents [Policy Text Block] Patents Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block] Stock-Based Compensation Income Tax, Policy [Policy Text Block] Income Taxes Comprehensive Income, Policy [Policy Text Block] Comprehensive Loss Earnings Per Share, Policy [Policy Text Block] Basic and Diluted Loss Per Common Share New Accounting Pronouncements, Policy [Policy Text Block] Recent Accounting Pronouncements Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table Text Block] Summary of the outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive Cash, Cash Equivalents and Investments [Table Text Block] Summary of cash, cash equivalents and available-for-sale marketable securities Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Summary of stock option activity Tabular disclosure of the allocation of equity-based compensation costs to a given line item on the income statement for the period. This may include the amount of total share-based compensation cost, including the amounts attributable to each share-based compensation plan and any related tax benefits. It includes the reporting line for the costs expensed. Schedule of Share Based Compensation Expense Allocation of Compensation Costs and Recognized Period Costs [Table Text Block] Schedule of stock-based compensation expense Schedule of Unrecognized Compensation Cost, Nonvested Awards [Table Text Block] Schedule of unrecognized stock-based compensation expense Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Schedule of future minimum payments for operating leases Income Taxes Income Taxes The percentage of valuation allowance on the deferred tax assets. Deferred Tax Assets, Percentage Of Valuation Allowance Valuation allowance on deferred tax assets (as a percent) Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share [Table] Antidilutive Securities [Axis] Antidilutive Securities Name [Domain] Antidilutive Securities, Name [Domain] Employee Stock Option [Member] Stock options Restricted Stock [Member] Unvested Restricted Common Stock Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] Anti-dilutive securities Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Outstanding securities not included in the computation of diluted net loss per common share as their inclusion would be anti-dilutive (in shares) Recent Accounting Pronouncements Lease, Practical Expedients, Package [true false] Schedule of Investments [Table] Financial Instrument [Axis] Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain] Major Types of Debt and Equity Securities [Domain] Debt securities due within 3 months issued by domestic or foreign corporate business, banks and other entities with a promise of repayment. Corporate Debt Securities2 [Member] Corporate debt securities due within 3 months of date of purchase Corporate Debt Securities [Member] Corporate debt securities due within 1 year of date of purchase Measurement Basis [Axis] Portion At Fair Value Fair Value Disclosure [Member] Portion at Fair Value Measurement [Member] Carrying Reported Amount Fair Value Disclosure [Member] Carrying value Estimate Of Fair Value Fair Value Disclosure [Member] Fair value Fair Value, Hierarchy [Axis] Fair Value Measurements Fair Value Hierarchy [Domain] Fair Value Hierarchy [Domain] Fair Value Inputs Level1 [Member] Level 1 Fair Value Inputs Level2 [Member] Level 2 Schedule of Investments [Line Items] Cash, Cash Equivalents and Marketable Securities Cash and Cash Equivalents, Fair Value Disclosure Cash and cash equivalents Represents the maturity period from date of purchase to classify an investment as marketable securities. Maturity Period from Date of Purchase to Classify Investment as Marketable Securities Maturity period from date of purchase to classify an investment as marketable securities Debt Securities, Available-for-sale, Amortized Cost Marketable securities, cost Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax Marketable securities, unrealized gains Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax Marketable securities, unrealized losses Debt Securities, Available-for-sale Marketable securities, fair value This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings, and cash and cash equivalents. Cash, Cash Equivalents, and Short-term Investments, At Cost Total cash, cash equivalents and marketable securities, Cost This item represents the gross unrealized gains for cash and cash equivalents securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities. Cash and Cash Equivalents and Available for Sale Securities, Gross Unrealized Gains Total cash, cash equivalents and marketable securities, Unrealized gains This item represents the gross unrealized losses for cash and cash equivalents securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities. Cash and Cash Equivalents and Available for Sale Securities, Gross Unrealized Losses Total cash, cash equivalents and marketable securities, Unrealized losses Cash, Cash Equivalents, and Short-term Investments Total cash, cash equivalents and marketable securities, Fair value Schedule of Collaborative Arrangements and Non-collaborative Arrangement Transactions [Table] Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items] Stockholders' Equity (Deficit) Represents the number of votes per share that common stockholders are entitled to receive. Common Stock Voting Rights Number Number of votes per share that common stockholders are entitled to receive Conversion of Stock, Shares Converted Preferred stock conversion ratio Number of voting rights of preferred stock. Includes eligibility to vote and votes per share owned. Include also, if any, unusual voting rights. Preferred Stock, Number Of Voting Rights Preferred shares number voting rights Sale of Stock [Axis] Sale Of Stock Name Of Transaction [Domain] Sale of Stock [Domain] Over Allotment Option [Member] Additional Shares Represents registered offering. Registered Offering [Member] Registered Offering Counterparty Name [Axis] Repurchase Agreement Counterparty Name [Domain] Counterparty Name [Domain] Represents Goldman Sachs & Co. Goldman Sachs Co [Member] Goldman Sachs & Co. LLC Type of Arrangement and Non-arrangement Transactions [Axis] Arrangements And Nonarrangement Transactions [Member] Arrangements and Non-arrangement Transactions [Domain] Represents Underwriting agreement. Underwriting Agreement [Member] Underwriting Agreement Stock Issued During Period, Shares, New Issues Number of shares sold by the entity Shares Issued, Price Per Share Issue price of stock Proceeds from Issuance of Common Stock Net proceeds after deducting commissions and other transactions costs Represents the maximum aggregate offering price the entity may issue and sell shares of its common stock from time to time, at the entity's option, according to at-the-market issuance sales agreement with third party. Common Stock Aggregate Offering Price Maximum aggregate offering price Represents the percentage of gross proceeds payable as commission during the period. Percentage of Gross Proceeds Payable as Commission Percentage of gross proceeds payable as commission Represents number of days of notice period for termination of sales agreement. Sales Agreement Termination Notice Period Days Notice period of termination of sales agreement Stock Issued During Period, Value, New Issues Value of shares sold by the entity Value of common stock and preferred stock, debt securities and/or warrants, rights or purchase contracts that remain reserved for future issuances under shelf registration with the Securities and Exchange Commission of the United States. Remaining Securities Under Shelf Registration, Value Remaining reserved amount under shelf registration Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Award Type [Axis] Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain] Equity Award [Domain]