Share-Based Payments - Summary of Company's Stock Option Activity (Details) $ / shares in Units, $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($) $ / shares shares
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Stock Options, Beginning balance outstanding \| shares	3,308,049
Number of Stock Options, Granted \| shares	640,158
Number of Stock Options Forfeited/Cancelled \| shares	(54,108)
Number of Stock Options, Ending balance outstanding \| shares	3,894,099
Number of Stock Options, Exercisable \| shares	1,960,235
Weighted Average Exercise Price, Beginning balance outstanding \| $ / shares	$ 7.14
Weighted Average Exercise Price, Granted \| $ / shares	6.93
Weighted Average Exercise Price, Forfeited/Cancelled \| $ / shares	10.16
Weighted Average Exercise Price, Ending balance outstanding \| $ / shares	7.06
Weighted Average Exercise Price, Exercisable \| $ / shares	$ 2.82
Aggregate Intrinsic Value, Beginning balance outstanding \| $	$ 8,308
Aggregate Intrinsic Value, Ending balance outstanding \| $	3,890
Aggregate Intrinsic Value, Exercisable \| $	$ 3,890

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iii)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

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- Definition

For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)-(4)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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Weighted average price of options that were either forfeited or expired.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)-(4)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

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- Definition

Gross number of share options (or share units) granted during the period.

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

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Number of options outstanding, including both vested and non-vested options.

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-Publisher FASB
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Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.

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Amount of difference between fair value of the underlying shares reserved for issuance and exercise price of vested portions of options outstanding and currently exercisable.

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